lt1738 Linear Technology Corporation, lt1738 Datasheet - Page 20

• Manufacturer Part Number: lt1738
• Description: Slew Rate Controlled Ultralow Noise Dc/dc Controller
• Manufacturer: Linear Technology Corporation

RELATED PARTS
LT1738
PART NUMBER
LT1683
LT1425
LT1533
LT1534
LT1576
LT176X Family
LT1777
LTC1922-1
LT3439
DirectSense is a trademark of Linear Technology Corporation.
20
TYPICAL APPLICATIO
TO 264VAC
90VAC
UNLESS OTHERWISE NOTED: ALL RESISTORS 1206, 5%
BR1: GENERAL INSTRUMENTS W06G
C2, C3, C4: SANYO MV-GX
INPUT FILTER IS REQUIRED TO ATTENUATE SWITCHING FREQUENCY HARMONICS AND PASS FCC CLASS B (LT1738 DOES NOT ATTENUATE THESE LOW FREQUENCY HARMONICS)
MAIN ADVANTAGE WITH LT1738 IS IT MAKES SUPPRESSING THE HIGH FREQUENCY NOISE AND EMI EASY. THIS IS PARTICULARLY USEFUL FOR MEDICAL DEVICES BECAUSE
THE AC LINE TO EARTH GND CAPS ON THE INPUT FILTER CAN BE ELIMINATED; ALLOWING THE DEVICE TO PASS THE EARTH GND LEAKAGE CURRENT MEDICAL SPECIFICATIONS.
X3
X1
165k
51k
12V
IN755 A
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
[phone] FAX: [phone]
2N2222
1M
1M
510k
250VAC
0.1 F
“X2”
DANGER: HIGH VOLTAGE
2N2222
510k
165k
V
BIAS
DESCRIPTION
Ultralow Noise Push-Pull DC/DC Controller
Isolated Flyback Switching Regulator
Ultralow Noise 1A Switching Regulator
Ultralow Noise 2A Switching Regulator
1.5A, 200kHz Step-Down Switching Regulator
Low Dropout, Low Noise Linear Regulator
Low Noise Step-Down Switching Regulator
Synchronous Phase Modulated Full-Bridge Controller
Ultralow Noise Transformer Driver
L1
+
56 F
35V
1.8nF
19.6k
3.9k
3.9k
100k
2W
U
14
16
15
5
6
7
8
9
SHDN
V5
SYNC
C
R
R
R
F
V
SS
B
T
T
VSL
CSL
IN
17
13
www.linear.com
10nF
Ultralow Noise 30W Offline Power Supply
LT1738
D1: MBR20200CT
L1: HM18-10001
T1: PREMIER MAGNETICS POL-15033
GND
U3
NC
19
BR1
11
10
PGND
GATE
V
GCL
NFB
CAP
BIAS
NC
CS
V
10
C
3
2
1
4
18
20
12
+
100 F
400V
470pF
5pF
MUR160
K
BA521
0.068
P6KE200A
600V
5pF
D4
1/2W
A
6
5
NOTE: PIN 2 OF LT1738 MUST BE LAID OUT
AWAY FROM FAST SLEWING NODES
MTP2N60E
CNY17-3
4
COMMENTS
Dual Output (Push-Pull) Current Mode Architecture.
Excellent Regulation without Transformer “Third Winding”
Push-Pull Design for Low Noise Isolated Supplies
Ultralow Noise Regulator for Boost Topologies
Constant Frequency, 1.21V Reference Voltage
150mA to 3A, SOT-23 to TO-220
Programmable dI/dt; Internally Limited dV/dt
Adaptive DirectSense
Kilowatts, Synchronous Rectification
1A Push-Pull DC/DC Transformer Driver
ISO1
3
1
1
3
6
5
T1
2
1k
12
11
7
8
COLL
A1
TM
0.1 F
330 F
G-F
LINEAR TECHNOLOGY CORPORATION 2001
V
A2
Zero Voltage Switching, 50W to
25V
+
3
LT1431
6
C2
LT/TP 1202 1K REV A • PRINTED IN USA
D1
U2
+
COMP
1k
RMIO
G-S
R
REF
TOP
2
5
+
4
8
7
C3
330 F
25V
V
OUT
+
38.3k
1%
10k
1%
0.22 F
C4
330 F
25V
1738 TA02
– V
+V
12V
2.5A
OUT
OUT
1738fa
1k